1. Field of the Invention
The present invention relates to a mobile communication system which transmits a data signal from a base station to a mobile station, a mobile communication method, and a mobile station suitably used for the same.
2. Description of the Related Art
As shown in FIG. 1, broadcast communication whereby one or a plurality of base stations 101 to 107 transmit common information (data signal) to unspecified mobile stations 301 to 3012 in predetermined areas all at once is known in a conventional mobile communication system.
As shown in FIG. 2, multicast communication whereby one or a plurality of base stations 101 to 107 transmit common information to a plurality of mobile stations joining in (belonging to) a specific group in predetermined areas all at once is known in a conventional mobile communication system.
However, there is a problem in that communication qualities of signals received by the mobile stations 301 to 3012 are different from one another depending on a propagation distance and a propagation environment between the base stations 101 to 107 and the mobile stations 301 to 3012, so that the number of times that the base stations 101 to 107 transmit (retransmit) the common information (data signal) is increased when retransmission of the common information is requested for each of the mobile stations 301 to 3012, in the conventional mobile communication system such as the broadcast system or the multicast system, in which the common information is transmitted to the plurality of mobile stations 301 to 3012.
Moreover, there is a problem in that it is necessary to carry out reception processing of a long signal containing a redundant signal for error correction even at a mobile station in which a communication quality of a received signal is good when the redundant signal for error correction is used in order to reduce the number of times the common information is retransmitted, so that power consumption of the mobile station becomes larger in the conventional mobile communication system.